Question: What do the following two equations represent? $x+5y = -4$ $-5x+y = 5$
Explanation: Putting the first equation in $y = mx + b$ form gives: $x+5y = -4$ $5y = -x-4$ $y = -\dfrac{1}{5}x - \dfrac{4}{5}$ Putting the second equation in $y = mx + b$ form gives: $-5x+y = 5$ $y = 5x+5$ The slopes are negative inverses of each other, so the lines are perpendicular.